The present invention relates to electrical parts, or components for surface mounting, such as a connector and a switch, which are adapted to be mounted on a printed circuit board.
Recently it has come into wide use to mount electrical parts or components, such as a connector and a switch, and electronic parts or devices such as various integrated circuits on a printed circuit board having conductor lands. In general, such electrical or electronic parts are called "surface mount parts" or "surface mounting parts". In surface mounting of electrical parts, terminals of required electrical or electronic parts are soldered to corresponding conductor lands formed on a printed circuit board by preparing a printed circuit board having predetermined wiring patterns and conductor lands formed by copper layers, printing soldering paste on the conductor lands to which terminals of the electrical or electronic parts are bonded, positioning the terminals of the parts on the soldering paste on the conductor lands in alignment therewith, and thereafter heating the printed circuit board to reflow (melt) the soldering paste. In this way, the simultaneous soldering of terminals of electrical or electronic parts to corresponding conductor lands on a printed circuit board is attained.
Conventional surface-mounting electrical parts of this kind have such a construction as shown in FIG. 1, which is disclosed in U.S. Pat. No. 4,991,059. A rectangular parallelepipedic body 11 has strip-like terminals 12 projecting out of its both sides. The terminals 12 have base portions formed in parallel to the bottom of the body 11 by being bent toward the bottom side of the body 11 and then bent outwardly to form connection portions 12a. These connection portions 12a are soldered to conductor lands 14 formed on a printed circuit board 13.
In conventional surface mounting, the terminals 12 in the case of FIG. 1 are bent in the vicinities of their base portions just projecting out of the body 11 and in the vicinities of their connection portions 12a in directions perpendicular to and parallel to the bottom of the body 11, respectively, as indicated by 15 and 16 so that the connection portions 12a are held in contact with the conductor lands 14 in parallel to the bottom of the body 11. However, since the bending accuracy is low, the parallelism between the connection portions 12a and the bottom of the body 11 and their heights are not accurate, and further, their reproducibility is low. On this account, it sometimes occurs that the connection portions 12a incline with respect to or do not make close contact with the surfaces of the conductor lands 14. Hence, the electrical parts are not stable in posture and in position. Therefore, soldering of the connection portions 12a to the conductor lands 14 is bad and the soldering strength is also low. Moreover, the accuracy of the sites for the attachment of the terminals is low and their reproducibility is also low. In addition, since the bottom surface of each connection portion 12a is connected to the conductor land 14, a wide area is required for soldering and there is a limit to the reduction of terminal spacing.